On 28 May 1998 Pakistan announced that it had conducted five (simultaneous) nuclear weapons tests, in response to the same number of nuclear tests by India. Only one detonation was detected by seismic monitoring stations. The preliminary source parameters of this event determined by the IDC (International Data Center) were as follows: ORIGIN TIME: 10:16:25.7 EPICENTER: 29.06N 64.82E. Subsequent analysis disclosed that the test was actually conducted in a horizontal shaft in Ras Koh [literally, "gate of the mountains", or "foothill"] mountain, some distance to the southwest of the seismic location.
The photograph of the Ras Koh test site was released a week after the test. Prime minister Sharif and Information Minister Syed Mushahid Hussain took two separate groups of journalists to the Ras Koh test site, at which point it was disclosed that the sixth test had been conducted elsewhere, in the Kharan desert.
A structural depression separates the Chagai Hills and the Ras Koh Range to the south, consisting of flood plains and areas covered with thin layers of salt. Outside the monsoon zone, Balochistan receives scanty and irregular rainfall (4 inches); the temperature is very high in summer and very low in winter. Apart from the Toba Kakar Range, which has scattered juniper, tamarisk and pistachio trees, the other ranges are largely devoid of vegetation. Most of the people, therefore, lead nomadic life, raising camels, sheep and goats.| # | JDATE | ORIGIN TIME | LAT | LON | MB | YIELD | YMAX | EVNAME | AUTHOR | EVID | WF |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1998148 | 05/28/98 10:16:15.8 | 28.950N | 64.720E | 4.9 | - | - | - | PDE-Q | 1440562 | 1570 |